Back-digging excavator



Jun 17, 1930.-v

E. J. WILSON BACK DIGGING EXCAVATOR Filed April 21,1927 Z5 Sheets-Sheet l June 17, 1930. E41. WILSON BACK DIGGING' EXdAVATOR :s Sheets-Sheet 2 Filed April 21, 1927 June 17, 1930.

E. J. WILSON BACK DIGGING EXCAVATOR Filed April 21, 1927 3 Sheets-Sheet 3 PatentedJune 17, 1930 i UNITED STATES PATENT OFFICE EMERY- J. WILSON, or CLEVELAND, c1110, AssIerioR To THE mmw snovEI. com- PANY, or LORAIN, 0211b, A CORPORATION OF OHIO BACK DIGGING- EXCAVATOR Application filed 1 m 21,

' This invention relates to excavating machines and more particularly to back digging ditchers in which the scoop or dipper is moved toward the truck or machine base during the filling or digging movement. Such machines, when provided with a-rigid dipper incapable of being tilted or turned on the dipper stick, do not maintain uniform or desirable angle or rake of the dipper teeth by accommodating them to the varying slope of the. surface, being excavated and, moreover, usually require closure controlled clippers with accompanying provision for closure operation, and when providedwith a tilting dipper can -not carry the load outwardly to a point beyond the boom end and there dump it in a restricted area, but at best have scattered the load during outward swing.

My invention has for its objectto provide an improved excavator of this type including a: tilting dipper requiring no closure, but provided with the necessary control devices by which its position may be accommodated to the varying slope and the most efficient angle or rake thereby main-- tained, and which also .may be carried out. and dumped in a restricted area. remote frolm the central axis and beyond the boom enc l1 .A.-=i:'-urtherv object is .to' provide an improved tilting dipper for connection to a dipper stick,- with aspecial arrangement of the dipper as regards its mounting on the stick and its balance or lack of balance around its pivot, as well as latching. or other devices enabling motion of the dlpper position; Fig. 2 is a detail view correspond- 1927. Serial No. 185,569.

ing to l and showingthe dipper in dumping position; Fig. 3 is a sideele'vaton on a larger scale of the dipper and its control devices; Fig. 4 is an elevation from the left in Fig. 3, parts being broken away;

and Fig. 5 is a diagrammatic view'illustratging a ditch. v

The invention may be applied to any ex.- cavator includinga swin ingboom and a dipper stick movable or a justably mounted thereon and to which my tilting dipper is connected. It is shown applied to a porting the operation of the excavator in digable excavator including a truck mounted upon a base 2 of the track laying tractor type upon which is a turn table supporting the operator.

At one end of the body is mounted 'the boom 10 turning upon the horizontal pivot 11 and capable of lateral swinging movement by rotation of the turn table. At a point intermediate of the boom ends pro- VlSlOIl is made for mounting a dipper stick 12 actuated by any suitable crowding engine. In the form shown the dipper stick is provided with rack teeth 12* engaged by a pinion 13 on a shaft. 13 provided with a sprocket wheel coupled by the chain 1 1 to a sprocket on shaft 11 from which a second chain 15 leads to the shaft 16 actuated by any suitable crowding engine. The dipper stick is mounted,as is usual, for rotation or swinging movement in a vertical plane around the shaft 13 and for longitudinal sliding motion in its mounting by actuation of the crowding engine. The hoistin line 7 passes from its Winding drum over a s eave 10 on the end of the boom and thence directly to the dipper stick, or, as shown, a loop of the line may pass over a sheave 17,. connected tothe dipper stick, the two "maintains or passing over two pulleys the line being dead ended, as at 7*. The drag line may likewise be suitably dead ended, as on the boom, and pass over sheaves 18 on the boom and a sheave1199connected" to a'yoke v.20 pivoted to the side walls of the bucket or dipper 22 at the pins 21, which extend laterally for a purpose which will later appear? The bucket or dipper, shown i detail in Figs. 3 and 4, is of scoop form. In other words it has no closure but is filledby the excavating movement and is dumped by tilting or turning it so that the load comes out through its onlyopening. It includes a scoop shaped body portion 23 provided with an' open mouth, along one edge of which-the digging edge-are the usual ends of the loop 10 and one end of teeth 24, the body being mounted to swing on trunnions 25 between the hook shape arms ofa yoke 26 rigidly attached to the dipper stick.

The axis of swinging movement of the dipper on thedipper stick atthe trunnions 25 is considerably ea center with reference to thecenter of gravity of the bucket either empty or loaded, the center of gravity being located at different points within approximately the restricted area A, Fig. 3, according to whether the dipper is empty or partially or wholly loaded. Therefore, under practically all conditions and excepting only as noted hereafter, the dipper tends to swing by gravity towarda position in which'it holds its 1oad,'the limit-of such movement being the engagement of the e):- tensions of pins21 in the'curved seat -portions of the hook shaped arms of yoke :26, or in the position shown in Fig. 1. Motion of the-dipper in the opposite direction--'the clockwise direction Fig. 1,-for dumping, Iis secured by the outward push ofthe crowding stick or by a pull on [the drag line or both.

For proper control of the dipper it is vprovided with latch means actuated automatically by the usual dipper control devices and therefore not requiring any specialiactuating line or device. The latching means shown includes a pawl 27 pivoted at 28 to a pin: or shaft mounted in the yoke, said pawl :having a tooth portion 29 beyond which isan extension or tongue 30. Adjacent the tooth29 and pivoted at 31 pawl are two generally elliptical cam members 31. The tooth .29 of the pawl cooperates with a series, four being (shown, of

, ratchet teeth 32 formed as part of a single member and lying between parallel guide ways or flanges 33 thereof, and beyond said member the scoop carries a fixed stopshoulder or abutment 34.

In the dumped position of the "dipper,

shown in Fig. 2, the tooth 29 engages the fixed stop or abutment 34, thereby limiting on opposite sides of the of the ways "33-and-ratchet teeth '32,.but the tongue or extension-30is still in engagement with thebucket wall and lying upon the ways 33: I f 'Q'the bucket is .now moved toward dumping position the cams 31 meet the curvedyends 33 of the ways 33 and swing back 3011 their pivots 31 until their rear shoulders 35 meet the fixed abutments 35' on the pawl 27, said cams thereupon ridin' up upon-the edges of the ways 33 and Ii ting thef tooth-29 above't-he level of the ratchet teeth'f32', enabling the bucket to be turned freel in the clockwise direction Fig. 1 until finally the cams ride, down over the far ends of .theways 33 andenable the-tooth 29 :to engage the stop abutment '34. If the bucket-is now moved in the counterclockwise,

direction, Fig. 1, the cams 31 meet the far have been com letely traversed over their mespectwe ways 33 to the position shown in Fig. 1 :and' then returned as before described.

Thepurpose of this arran ement and the reasons I scribed will'appear hereafter.

Refer'ring-now to .Fig. 15, whichv illustrates l8. r1111 sequence of operat'ion of the excava- .tor,"let itbe assumed'that the cycle of operations begins with the bucket in the position shown in 'full lines lat position A, to wit, "the dumped position, zit z-b'eing understood of course "that the turn table may be swung around more or less, from the plane of di ging 'motion'to-dump the load out at one 'si eat the ditch being-excavated, which extends ;in the direction of travel of the excavator. In this dumping position A it will be-observed thatithe crowding stick has been pushed out'to itsa 'limi't and is hoisted nearly :to parallelism with the boom. The bucket has been dumpedfby a pull of the drag line. .Its center of gravity is inwardly of its axis of swingianditttendsto remain in'the dumping position'and to beheld there by the en- -,gage-1nent of pit-W127 against the limit stop 34. By "proper actuation of the drag and hoisting lines the dipper stick is-inoved downwardly to position 13.,with the bucket teeth forced into the ground. This occurs. only in starting a ditchor in the first opening of the groundLanrl the-operation when :full depth is reac'hed will be explained more fu-ll-yihereatter. Upon reachin position B, the crowding stick is pushe' outwardly,

or operation" of t he'parts as deusing the teeth of the bucket as a" fulcrum against the ground, the motion ofthe crowd ing stick causingthe buckettoflturn as the digging proceeds, until finally. its center of gravity is outwardlyof-its center of tilt on the di per stick whereupon the gravity effect o the bucket moves it more and more toward the final filled position. The bucket sweeps are extended more and more until finally the bottom of the ditch is reached. Now, after each dumpingjoperation the bucket is brought downv to position C in which gravity turns it to a position with its fiatbottomor wall parallel with the ditch bottom. It is advanced intothe earth and is caused to move up the slope successively through positions D and E. During this movement the drag line and crowding engine are relatively manipulated not only to advance the bucket along its path of cut but to also perm-it gravity to progressively change the bucket position by progressive tilt upon the dipperstick'so that the angle or rake of the teeth ismaintained uniform with respect to the slope of the surface being excavated. 'As the cut proceeds the excavated material falls into the bucket and more'and more assists in turning it to maintain uniformangle-or rake. \Vhenposition E is reachedrand the cut is completed the drag lineisslacked off topermitthe bucket to settle fully to load maintaining position 7 with its pin extensions .21 settled in the crotches 'of the hook shaped yoke arms .26 and the bucket is moved through a series of positions F outwardly topthe position shown in dotted lines at A. During such outward motion or after it is completed the boom may be swung laterally to the side of the ditch and throughout the movement the po-- sition ofthe bucket is suchas to maintain the load and not permit it'to spill; When dotted position A is reached the crowding stick is held and thezdrag'line is drawn in or the drag line is held and the stick is crowded out to tilt and overbalance the bucket and. permit its load to drop within a practically anywhere within the range 0 the bucket and not necessarily at the farthest point from the center.

This invention, "among others, has two di'sa tinct advantages.

In digging a narrow ditch it is possible to carry each load outwardly laterally to a point considerably beyond the edge of the ditch and there dump it, so that it. is unnecessary as in prior constructionsto either dump the load close to the edge of theditch or to scatter it over the ground as the bucket is moved outwardly. Liability of crushing in the walls of the ditch bythe weight of material deposited' upon them is therefore obviated Also, in

excavating up .alon 1 the slope "throu h ositions. C, D, and theangle of rike is varied to meet the variation inuslope and the teeth of the bucket'are alwayspresented at *the most eflicient cutting angle and are not dragged acrossthe slope while standing out vertically .or perpendicularly thereto.

. 'Wh-atI claim is:

1. Anexcavator provided with a swingdng boom, a dipper-stick mountedQthereon, a. dipper mounted to swingon said stick and balanced to normally tend when loaded to swing toward a load maintainingposition, a drag line operatively connected to said dipper in a position to a dump said. dipper when loaded, and. holding means .between said stick and said dipper for resistingthe drag line pull to maintain thedipper in a plurztliltiy of digging positions on the dipper s 10 w 7 I 2. An excavator provided with a swingin boom, adipper stick mounted thereon, a ipper mounted to .swingon said stick and balancedv to inormallytend when loaded to swing toward a load maintaining position, a. drag line operatively connected tofsaid dipper, and self 'actin'g. holding means for resisting the drag line pull to maintain the dipper in aplurality of digging positions on the-dipper. stick. .i v 3. An excavator provided; with a swinging boom, adipper stick mounted thereon, a dipper mounted to swing on said'stick and balanced to normally tend whengloaded to swing; toward a ,loadfgmaintaining position, a drag line operativel connected to said dipper, selfacting ho ding meansfor re- "sisting .theidrag line pull to maintain the dipper in a ,plurality-ofdigging positions onthe dipper stick, and means forovercom :ing the-effect of said holding means for dumping saiddipper.

4.. An excavator as in claim 2 wherein the holding meansis i-nvtheform of ratchet andspawl mechanism arranged between the dipperstick andthe scoop.

An excavator as inclairn 2 wherein the holding means is in the form of ratchet and pawl mechanism arranged between the dipper stick and'the scoop and comprising a pawl carried by, the di per stick, and a plurality of teeth carried by the. scoop and adapted to engage the pawl.

r 6. An excavator as in claim2 wherein the holding meansis in "the form of ratchet and pawl mechanism arranged between the dipper stick and the scoop and comprising a pawl carried by the dipper stick, a plurality; of teeth carried by the scoop and adaptedlto engagethe pawl, and means for raising said pawl out of the range of said teeth and effective i when the dipper is thrown to extreme load maintaining position.

. Anezrcavator as in claim'2 wherein the.

holding means is in the form of ratchet and pawl mechanism arranged between the dipper stick and the scoop and comprising a pawl carried by the dipper stick, a plurality of teeth carried by the scoop and adapted to engage the pawl, means for raising said pawl out of the range of said teeth and effective when the dipper is thrown to extreme load'maintaining position and comprising a cam member carried by the pawl and the cooperating rail carried by the dipper.

8. In an excavator, a swinging boom, a dipper stick mounted thereon and movable to a position in which it extends outwardly beyond the boom end, a dipper pivoted to said stick with its piwital point toward the front and near the bottom of said dipper whereby it may swing toward load maintaining position when loaded and toward extreme dumping position when its center 7 of gravity is swung forward of said pivot,

the pivot and tending a drag line connected to said dipper above throughout its various positions to swing it tion, and holding means for resisting the drag line pull to maintain the dipper in a plurality of digging positions on said stick.

9. In an excavator, a swinging boom, a dipper stick mounted thereon and movable to a position in whichit extends outwardly beyond the boom end, a dipper pivoted to said stickwith its pivotal point toward the front and near the bottom of said dipper whereby it may swing toward load maintaining position when loaded and toward extreme dumping position when its center of gravity'is swung forward of said pivot, admg line connected to said dipper above the pivot and tending throughout its various positions to swing it to dumping position, and holding means for resisting the drag line pull to maintain the dipper in a plurality of digging positions on said stick antl comprising ratchet and pawl mechanism arranged between the sticlcand dipper. 10. In an excavator, a swinging boom, a

1 dipper stick mounted thereon and movable to a position in which it extends outwardly beyond the boom end, a dipper pivoted to said stick'with its pivotal point toward the front and near the bottom of saiddipper whereby it may swing toward load maintaining position when loaded and toward" extreme dumping position when its center of gravity is swung forward of said pivot, a drag line connected to said dipper above the pivot and tending throughout its various positions to swing it to dumping position, holding means for resisting the drag line pull to maintain the dipper in a plurality of digging positions on said stick and comprising ratchet and pawl mechanism arranged between the stick and dipper, and

stop means arranged between the stick and to dumping posi signature. a

EMERY J. WILSON. 

